Trait XactStatusOracle 

pub trait XactStatusOracle {
    // Required method
    fn status(&self, version: u64) -> XactStatus;
}

v7.37.15 (Phase C.2) — the visibility oracle: maps a version id to its terminal XactStatus.

spg-storage (no_std) defines the contract; the real registry (a sharded DashMap<u64, XactStatus>) lives in spg-engine and implements this. Kept as a trait so the visibility rule stays in storage next to Snapshot::visible without storage depending on the engine’s concurrency primitives.

Required Methods

fn status(&self, version: u64) -> XactStatus

Terminal status of version. Implementations return XactStatus::Committed for any version they no longer track (pruned below oldest_active, or frozen) — those are, by definition, committed-and-old.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors

impl XactStatusOracle for AllCommitted

impl XactStatusOracle for Engine

v7.37.15 (Phase C.2) — the engine is its own visibility oracle. Scans hold &Engine while reading, so a scan site can pass self as the XactStatusOracle alongside its Snapshot when the visibility gate migrates from visible to visible_with_status (next Phase C step). Delegates to Engine::xact_status.